Surface Grinding Attachment - SGA

J. Keeton

J. Keeton

Active Member
I figured some of yall here could get something out of this build. This video goes though my "Travis Wuertz SGA Clone" build step by step. There is a parts list included product links in the description of the video. I also have a PDF drawing in there that could help with a build.

Thanks to the internet I was able to stand on the shoulders of giants with this build and copy the work of many good blade makers. I hope this video was able to put the required steps together in a concise and easy to understand format.




Cheers,
JKeeton
 
Welcome to the “DIY SGA Builders Guild”! Travis Wuertz designed an amazing machine that some like us could duplicate. All it took was finding the parts & figuring out how to build a magnetic Chuck. Yes.. that certainly is some thread on Blade Forums. Who was it that started that thread again?? LOL!

Good stuff man! Always makes me smile to see another follow suit
 
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One Armed said:
Welcome to the “DIY SGA Builders Guild”! Travis Wuertz designed an amazing machine that some like us could duplicate. All it took was finding the parts & figuring out how to build a magnetic Chuck. Yes.. that certainly is some thread on Blade Forums. Who was it that started that thread again?? LOL!

Good stuff man! Always makes me smile to see another follow suit
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Hey man, you are the legend. Thanks for starting that thread! Great design there. I'm extremely happy I came across it! This is way cheaper than buying one off the shelf and it's a fun project to boot!

I can't wait to put some hours behind it now.
 
Oh no...I’m nothing special.... Travis Wuertz is a TRUE genius, who designed a fantastic tool. I was simply blessed with great “searching” ability. And... I’m super CHEAP! LOL:D I can pinch two-bits into a couple dimes & a nickel!

Seriously, just as all of us doing this, I have a true passion for “building” things. I know I’m not the only one who enjoyed building a 2 x 72 grinder as much as making knives. I started that thread never thinking it would spark what is has. Ken contacted me through that thread & him & I have become very good friends because of it. He brought it over here, and Stromberg did the incredible write up & CAD pics of his. I believe it was he who also found the POV Slide Table(like you are using). And those wanting to build their own slide tables can still follow either Ken’s or my original concept design from the original threa

It has been my pleasure to see the different ways each of us has tackled the project. Some truly AMAZING machining skills by you guys!

Thank you J. Keeton for your great video. Very entertaining my friend.
 
Hey J, something else came to mind while watching your video....you should do a 45 degree angle tooling arm setup, as I have. It works SOOO much better than straight up & down. And honestly, I think it’s better than horizontal as well.

Here is my setup now. And the beautiful finish it leaves.

 
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One Armed said:
Hey J, something else came to mind while watching your video....you should do a 45 degree angle tooling arm setup, as I have. It works SOOO much better than straight up & down. And honestly, I think it’s better than horizontal as well.

Here is my setup now. And the beautiful finish it leaves.
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Hey man, I thought about it, but wanted to keep the build design as simple as possible. Do you mean it's better as far as the results achieved or just easier to use? Just wondering if there is any advantage of having gravity work down on the slide table seating it into the bearings better?

I can see that it would be easier to operate for sure.... I guess I need to find out how to pivot my grinder 90 degree...
 
Just much easier. Results are the same no matter vertical, horizontal or 45 degree angle. But I find 45 degree most comfortable & the ground material can easily be directed into a bucket for the most part, keeping things much cleaner. Overall it’s more enjoyable.

Ya know J, I don’t really have SOP’s. If you know anything of me, you may know I’m disabled and have a paralyzed left arm/hand. I’ve been a Knifemaker for close to 8 years, the last 6 years being disabled. As a result, I am demonstrably slower than most others. But this has given me an extreme patience. When I use my SGA I simply go slow and steady. I am only methodical in my planning ahead of time. Funny, I was just talking to Ken here about this. Him and I both do it....planning things so carefully that I almost never make any mistakes. So I don’t really follow steps other than taking my time. I will make a initial pass almost “creeping” the blade along the wheel. Then I will continue going back & forth until I barely can hear the belt contacting the blade surface. The picture I posted is right off the SGA... NO hand sanding. And no, I do not shim as I’ve no need. I use only CPM3V & CPM20CV steels EXCLUSIVELY. The steel is for the part very flat already. Typically just mill scale which I remove with an overnight soak in Muriatic acid.
 
I was thinking about how to write this, then OneArmed chimed in with his ideas. He's right, doesn't matter what position the grinder is in for results, they're all going to be the same. I built my SGA for horizontal use, mostly because that's how Travis built for the TW90. OneArmed did his with 45 angle and it sounded good, so I changed my SGA to 45 angle with the idea it would keep the shop a tad cleaner due to grinding dust being thrown downward to bucket. It works good that way, but I think because I'd already gotten used to horizontal, it just seemed to work better for me. Once I use something a while, I'm accustomed to it and don't tend to change things unless there's a need for change.

Like OneArmed I tend to plan things, sometimes to the point of "overplanning", but I still make more mistakes than I'd like to. Especially as I get older it seems I'm more clumsy and make more mistakes, takes longer for eyes to focus when moving from one object to another. That was the BIG driving force behind me selling my Goldwing motorcycle last yr, too many little huh-ohs happen, and concerned they would happen on bike. A motorcycle isn't a place to make an huh-oh, a minor fender-bender for the car can be drastic for a bike. Selling the bike was a big deal for me, bikes have been basic transportation for me since I got my first "big bike", a '74 Harley when I was 15 yrs old. An old 1955 panhead with foot clutch, hand shifter, and kickstarter. Boy, those were the days!

Later
 
Thank you sirs for the tips! Guess I need to just get better at getting my warps out in tempering before heading to the SGA!
 
KenH said:
motorcycle isn't a place to make an huh-oh, a minor fender-bender for the car can be drastic for a bike. Selling the bike was a big deal for me, bikes have been basic transportation for me since I got my first "big bike", a '74 Harley when I was 15 yrs old. An old 1955 panhead with foot clutch, hand shifter, and kickstarter. Boy, those were the days!
Later
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You ain’t kidding in that Ken! I was riding my when the accident that disabled, paralyzed & almost cost my life happened! Though I didn’t make the “mistake”. Someone causes me to separate from my bike & I was run over by an SUV.

Sorry to go off topic...but I had to reply to what you said Ken.., LOL!
 


So far these are my results. I surface ground 3 knives post HT... Granted I was learning the machine here so I ended up taking of more than I should have on them. (especially the top one)

To mitigate any warping issues and to see how true my SGA was I took a piece of .25'' plate and surface ground it (@ the bottom there).

The x marks where I measured with the mic. The circled number is the "max variance" across the points I measured.



So it looks like I'm right at 1 to 2 thousandths of an inch accuracy across these pieces. Two interesting things just looking at this sheet is that the lower measurement on the tang is consistently smaller... and the center measurement on the bottom two knives is the largest across the knife.

What do yall think?

Cheers,
JK

EDIT: That bar is about 7.5'' long
 
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I think that +/- .001" for the length is pretty good. "Precision ground" is generally about half that. So not too shabby at all.
 
Good stuff man! .001-.002” is on par with the results of every SGA, including Travis Wuertz original.

Any belt style Surface Grinder is going to have similar results. The stone Surface Grinders can hold a couple tenths accuracy across a piece...I’m talking .0002”! Insane! But remember, how many thous./inch can the human eye pick up? Probably around .010 or more?? Maybe a little less??..however, no one can “see” even a .003” difference on a blade.

Your results are good J. Like I said, right in league with all of us. Enjoy it.
 
1 to 2 thou is pretty good and is in the same ballpark as rest of us get in general use. You did lightly touch the surface of the magnetic chuck with belt before doing any grinding? That's important, and should be a long time before it needs doing again.
 
Oh yes! I forgot that... Thank you for pointing that out Ken. Ya know, that is one of those little details that needs be addressed in every SGA thread. Making certain the magnets are set deep enough in the Chuck for surfacing, from the start! (I set the magnets approx .100” bellow the surface.) As it doesn’t matter where the two components are in relation to the axis of the grinder.... only that the the Wheel Surface and Magnetic Chuck Surface are PARALLEL to one another.
 
Yes Sirs, I did surface the chuck. I did it with a 2'' belt tracking back and forth. I plan on getting a 3'' belt soon to touch it up again... just to make sure.

I set my magnets fairly deep @ 0.125''.

I'm glad to hear my results are in the range! I mainly work on fixed blades so this will be prefect for me. I'll have to make a scale holder next like Stomberg!
 
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